What is a 410 screw

410 screw" is likely a misinterpretation or confusion with .410 bore shotgun designation, which isn't a screw at all but rather a shotgun bore diameter (approximately 10.4 mm or 0.410 inches). True screw designations don't use decimal numbers in this format—screws are specified as numbered gauges (#0-#14), fractional inches (like 1/4"-20), or metric (M3, M4, etc.). If the question refers to an actual screw, clarification is needed on the measurement system and specification format.

Alternatively, this might reference a screw designated "4-10" meaning #4 gauge screw with 10 threads per inch (an uncommon but possible sheet metal screw specification), or possibly a metric screw with dimensions near 4.10 mm. Without proper context from the source document or application, "410 screw" doesn't correspond to standard fastener nomenclature. When encountering unfamiliar or non-standard fastener designations, examine the actual hardware with calipers or micrometer to determine diameter, measure thread pitch with a thread gauge, and identify head style before attempting procurement or replacement. Many specialized industries (aerospace, medical devices, antique restoration) use proprietary or obsolete fastener standards that don't match modern commercial catalogs, requiring custom manufacturing or specialized suppliers. Document unusual fastener specifications with photographs, measurements, and application notes to facilitate future replacement or maintenance requirements.